Meter



July 8,1941. LEIN ETAL 2,248,429

METER Filed July 15, 1938 2 Sheets-Sheet 1 July 8, 1941. M. KLEIN ET'AL METER Filed July 13, 1938 2 Sheets-Sheet 2 32% MWPWZM'I/ Patented July 8, 1941 lWETER Maximilian Klein and Eeidar A. Tollefsen,

Sellersville, Pa., assignors to United States Gauge Company, Sellersvillc, Pa., a corporation of Pennsylvania Appiication July 13, 1938, Serial No. 219,075

8 Claims.

is invention relates to recording or indicating apparatus, and is more particularly concerned with apparatus for making indications or records of a condition for he purpose of assisting and permitting accurate control and study of at least certain phases of that condition.

The invention is of general application in that it can be used for indicating and recording any desired conditions, but its peculiar suitability in the solution of a problem long existent in the oil well drilling industry will now be discussed briefly.

In drilling oil. wells, the bit is ordinarily mounted upon the lower end of a rigid hollow drill pipe whose upper end is provided with a cable attached to a suitable hoist. During drilling operations, the drill is partially suspended in the hole to be drilled by means of the cable, and partly rests on the bottom of the hole. An operator, standing at the brakes of the hoists, tries to maintain a predetermined allowable drill pressure at the bottom of the hole by controlling the suspended weight of the drill.

For observing this pressure many operators use a so--called weight indicator, which is attached to the cable at the hoist and indicates the suspended weight of the drill at any time. For exampie, when the drill is wholly suspended in the hole and not resting upon the bottom, the weight indicator gives its highest reading which represents the total weight of the drill. As the drill lov id into contact with the bottom of the hole, the suspended weight decreases and the ing on the weight indicator decreases until finally, if the cable is allowed to slackcn with the entire weight of the drill supported in the hole, the weight indicator will read zero.

In practical oil well drilling, the total weight of the drill is never allowed to rest on the bottom ol the hole and the drill is maintained partially suspended in the hole. The difference between the total weight of the drill and the suspended weight of the drill is known as the load on the bottom of the hole. The suspended weight of the drill is indicated on the weight longer. In order to maintain this load on the bottom constant, the operator at the hoist watches the weight indicator and tries to keep the pointer thereof at a certain predetermined place during drilling. Some operators use a recorder in place of, or along with, the weight indicator, to make the record of the suspended Weight of the drill. This recorder merely records the same suspended weight as indicated on the weight indicator.

In actual practice the allowable loads on the bottom are very small, being represented on the conventional weight indicator or the conventional recorder by only a few scale divisions, since the total suspended weight is usually so much larger in proportion than the allowable load on the bottom and it is very diificult for the operator to maintain the predetermined load on the bottom merely by watching his indicator or recorder. The recent trend, moreover, is toward decreasing the permissible load on the bottom and it is becoming increasingly important to be able to maintain that permissible load on the bottom accurately during drilling operation.

The recording and indicating instruments in use at present as above described, do not permit an accurate determination of the actual load on the bottom and do not present a clear indication of variations in that load on the bottom because they indicate or record the total suspended weight and hence must be calibrated upon relatively small scales. In fact, in some recorders, the thickness of the recorded line alone often represents about 33 to 50 per cent of the allowable load on the bottom. Hence, it has become desirable to develop apparatus which will give a magnified indication or record of the load on the bottom, as maintained during drilling operations, so that the operator may be enabled to control the load more accurately. Also, a clear record of the load and any variations therein can now be obtained for study by the engineering office and for checking up on the accuracy of the operator.

With solution of problems such as the above in mind it is a major object of the invention to provide novel recording and/ or indicating apparatus operable to make a magnified or amplified record and/or indication of a condition dur ng a predetermined phase of that condition. .fically, as applied to the art of oil Well drilling, the invention is designed to provide a nagnified record and/or indication of the load on the bottom of the hole during actual drilling operations.

A further object of the invention is to provide novel recording apparatus for making separate synchronized records of the same condition, one of the records representing an amplified or magnified embodiment of a portion of the other record. As specifically applied to the art of drilling oil wells, one apparatus records the suspended weight of the drill at all times while the other apparatus records the load on the bottom during drilling operations only.

It is a further object of the invention to provide a novel recording apparatus having a plurality of recorder arms having different amplitudes of movement but both controlled by the same condition. The recorder arms operate concomitantly during certain phases of the condition.

A further object of the invention is to provide recording apparatus having novel arrangements for rendering the recording apparatus inoperable by the actuating means which is energized by the condition to be recorded. Specifically the recording apparatus is provided with a recorder arm connected to a pressure responsive actuating element by a releasable clutch.

It is a further object of our invention to provide novel recording apparatus wherein a movable recorder arm is actuated through a releasable clutch mechanism which is manually controlled by a suitable clutch release element.

A further object of our invention is to provide novel recording apparatus wherein two recording arms make separate records of different amplitude of at least portions of the same condition. One of the arms makes a record substantially during the whole period that the condition exists while the other arm can be locked for concomitant movement with the first arm during a predetermined portion of the condition to give an amplified record of the condition at that time. Preferably both records are made on the same chart with the arms moving in opposite directions, so as not to interfere with each other.

A further object of the invention is to provide a novel recording apparatus wherein a pair of separate recorder arms are connected to separate pressure responsive elements actuated from a common source responsive to the condition to be recorded. Specifically, one arm is selectively operable only to give a large scale version of a predetermined portion of the record made by the other arm 50 that the records may be used for close scrutiny of actual operating factors existing during the time that predetermined record portion was made.

Further objects of the invention will appear as the description proceeds in connection with the appended claims and the annexed drawings in which:

Figure l is an enlarged view in side elevation of a recording apparatus constructed according to the principles of the invention.

Figure 1A is a fragmentary view illustrating the recorder arm linkage of Figure 1 upon a larger scale.

Figure 2 is a section taken generally along line 22 in Figure 1A illustrating the support arrangements and the pressure responsive actuating element for the separate recorder arms.

Figure 3 is an enlarged section taken along line 3-3 of Figure 1A illustrating further the recorder arm support arrangements and the manually operable clutch control member.

When the invention is employed in connection with oil well drilling apparatus or some other apparatus where an operating tool such as a bit suspended from a cable or the like is used, the cable may be connected to a suitable fluid pressure generating device for translating changes in tension on the cable due to the load of the tool into variations in fluid pressure which may be recorded by the instrument illustrated in the drawings. This instrument, of course, is adapted for use with any suitable source of fiuid pressure regardless of how the pressure variations are produced therein.

A novel recording apparatus designed for these uses will now be described.

The recording apparatus is mounted in a casing 22 having a closed bottom wall 23 and a circumferential flange 2-1 extending beyond the casing in alignment with wall 23. Preferably casing 22, wall 23 and flange 24 are integral and provide a substantially cup-shaped container for receiving the recorder apparatus. Casing 22 is provided with a face plate 25 seated upon an internal shoulder 26 formed in the casing walls. As shown in Figure l, casing 22 is provided with a plurality of lugs 21 having tapped holes 28 for receiving suitable screws (not shown) for securing plate 25 within the casing. Plate 25 is apertured at 29 to permit extension and free movement of recorder arm mechanism which will be later described. Flange 24 is provided with a plurality of apertures 3| for accommodating suitable fastening means (not shown) by means of which the whole apparatus may be mounted upon an instrument board or the like.

A shaft 32 extends axially of casing 22 and projects through a suitable aperture in plate 25 to support a suitable ruled recording chart 33 which is non-rotatably secured thereto by a suitable fastening means 34. Shaft 32 is rotatably driven by means of a suitable clockwork or other similar timing mechanism to advance chart 33 past the recorder arms as will appear later. Shaft 32 and the mechanism for rotating the same may be of any desired conventional construction known in the art and will not be de scribed further since the invention is not concerned with that specific mechanism.

Inside the bottom wall 23 is secured, as by screws 35, a plate 36 supporting a hollow post 31 of some thin relatively rigid material. Post 31 extends through plate 38 and wall 23 and is connected with a fluid pressure conduit is which leads to a suitable source of fluid pressure capable of varying in response to changes in the condition to be measured.

A pair of relatively fiat, flexible, curved hollow pressure responsive elements 33 and 33, which are preferably of the well known Bourdon tube type and are made of thin flexible metal or some similar material, are each supported at one end in axially displaced relation, upon post 31. Post 31 is in fluid communication with conduit l8 and each of elements 33 and 39 so that elements 38 and 33 are both subjected simultaneously to the fluid pressure of the source to which conduit l8 may be connected.

Bottom wall 23 (as illustrated in Figures 1A and 2) is provided with an upstanding arcuate ledge formation 4| upon which is rigidly secured in some suitable manner, as by screws 42, a flat generally rectangular plate 43 of metal or some rigid material. Plate 43 has non-rotatably secured thereupon, at its two inner corners, a pair of upstanding posts 44, which are bridged by a relatively narrow bearing plate 45. Posts 44 and plate 45 are, preferably, rigidly secured together as by screws 46. At the outer corners ofv plate 43 are non-rotatably secured twomore posts (not shown but similar to though longer than posts 44) for supporting a pair of vertically spaced bridge plates 47 and t8. Suitable bolt means designated at 48 maintain plates 4'! and dilrigidly in spaced relation with respect to plate 43. As shown clearly in Figures 2 and 3, plates 53, 45, 11 and 33 are all parallel and plates ll and 48 are substantially coextensive.

A shaft extends axially of casing 22 and is non-rotatably supported at its opposite ends where it traverses plates 43 and ea. Preferably end sections 52 and 53 of shaft 5! are squared, or otherwise out of round, to cooperate with similarly shaped apertures in end plates 43 and id respectively. Shaft 5! is provided with enlarged cylindrical collar formations 54 and 55 of the same diameter adjacent its opposite ends, and the cute edges of collars 54 and 55 lie substantially flush with the inner surfaces of plates '33 and it respectively. Collars 54 and 55 thus provide effective shoulders which abut against plates and it and when bolts M are tightened shaft 5| is rigidly secured between plates 43 and 48. he peripheral surfaces of collars 54 and 55 are preferably perfectly cylindrical and smooth to serve as bearing surfaces as will later be descril ed.

Shaft 54 is provided intermediate its ends with a further collar formation 56, which extends through a suitable closely fitting aperture in supporting plate 5i. Collar 55 extends axially a substantial distance beyond plate ll for a purpos later to be described. ihe peripheral surface of collar is perfectly cylindrical and smooth and collar 55 is of the same diameter as collars 5 and At its outer end, shaft 5! supports a freely rotatable cylindrical sleeve ill, which is rotatably supported ad acent its ends upon collars 55- and and whose opposite ends are disposed substantially in engagement with adjacent surfaces of plates 3? and to prevent axial displacement of sleeve along the shaft beyond the support ing bearing surfaces of collars 55 and 55.

Sleeve 57 is provided, adjacent its outer end, with a reduced portion 58 about which is nonrotatably fastened one leg 59 of a generally U- shaped bracket 55, whose other leg 62 is apertured at *3 for mounting a suitable recording arm, as will later described. A suitable fastening means 64 which may be integral with sleeve 5?, if desired, secures bracket Ell against movement axially of shaft 5 l. Adjacent its inner end, sleeve 5'! is provided with a reduced portion 65, upon which is non rotatably secured one end of an arcuate arm A suitable fastening means 6?, similar to that at lid, retains arm 6% against movement with respect to shaft 51.

As shown in Figures 1 andlA, arm. SE5 is pivotally and adjustably connected to one end of a link (it by means of a suitable pivot screw assembly 58, which extends through a suitable aperture adjacent the forward end of link and through an arcuate slot ll fOl'lT-Gil in arm Pivot assembly Gil (see Figure 53) is provided. with an enlarged socket head ii! at one end and an enlarged screw head l3 at the other end. Vhen screw i3 is tightened the pivot assembly 58 is locked in a fixed position along slot H but link 58 is freely pivoted to assembly 58 at all times.

The other end of link G8 is pivotally connected to the free end of the pressure responsive element 33, by means of a pivot screw '14, whose shank extends through a suitable aperture in the lower end of link 68 into threaded engagement with a lug l5 integral with, or rigidly secured to, element 38.

Thus it will be seen that as element 38 flexes in response to pressure changes in the source, link 68 will be displaced to cause rotation of arm 65, sleeve 5'! and bracket Eli about the axis of shaft 5 l. Sleeve 5! is supported by spaced bearing surfaces at $5 and 56 and there is very little frictional resistance to this motion.

A second freely rotatable sleeve 15, substantially longer than sleeve til, is supported along the inner portion of shaft 5i. The opposite ends of sleeve it are rotatably supported upon collars 54 and 5G and opposite edges of sleeve 76 are substantially in engagement with adjacent surfaces of plates 43 and ll to prevent axial displacement of sleeve :6 along shaft 5! beyond the bearing surfaces at 54 and 5%.

A concentric clutch element Tl is slidably and rotatably mounted upon the outer portion of sleeve Hi, which is of lar er external diameter than the inner portion. Element l! is provided with a reduced portion 18, forming a ledge upon which is non-rotatably seated one leg 19 of a generally U-shaped recorder arm bracket 8|, Whose other leg 32 is apertured at 552 for mounting a suitable recorder arm as will be later (18-- scribed. A suitable fastening means 33, which may be integral with element ll, prevents movement of bracket 8| axially of shaft 5!.

Element l1 terminates short of the outer end of sleeve 76 and is surrounded by a coil spring 24 which extends between a wide peripheral flange adjacent the end of sleeve l6 and the inner surface of bracket leg i9. Spring 84 tends V to displace element l? to the right in Figure 3.

At its other end, clutch element Tl is provided with an enlarged head 99 having a substantially conical surface 85 which. terminates in an an.- nular ledge ill. Surface 85 is preferably knurled or otherwise roughened and is provided with a relatively deep inclined groove 83 whose line of direction lies in a plane containing the axis of shaft 5!, for a purpose later to be described. Groove 38 is generally bani-cylindrical in crosssection and is preferably provided with a smooth internal surface. An annular ring 223 of cork or some similar relatively resilient material, having a high coefiicient of friction, is secured upon ledge ill by a suitable cement or in some other similar manner.

A second clutch element is rotatably and slidably supported concentrically upon spaced bearing shoulders s2 and s3, formed upon the reduced portion of sleeve l6, and is provided with annular 9d non rotutably secured upon the outer end thereof and maintained against axial displacement by a suitable fastening means 95. Beyond ring clutch element 9! is formed with a plurality of axially extending gear teeth as; and beyond gear teeth 98, clutch element Si is reduced in sire and has non-rotatably mounted thereupon a ring 9?. Ring 97 is grooved at its perlp -ery to seat the inner convolution of a coiled fiat hair spring 98, one end of which is attached to ring The other end of hair spring 9%; is attached to any suitable part of the apparatus rigid with plate Hair spring tends to urge sleeve 15 to rotate in a predetermined direction for a purpose to be explained later. Excessive axial 4 2,24ai2o movement of clutch element 9| is limited at one end by the shoulder 99 at the inner edge of the enlarged portion of sleeve I6, and at the other end by a ring lGI non-rotatably secured adjacent the inner end of sleeve I6 by a suitable fastening means I92.

Adjacent lateral faces of friction ring 89 and ring 94 function as cooperating friction clutch laces as will appear later. The teeth of gear 96 are engaged by teeth I63 of a gear segment I94 which is suitably non-rotatably secured to a pivot shaft I85, extending between spaced end bearings in plates 43 and 45. Shaft I95 is parallel to shaft Segment I94 is adjustably and pivotally connected to one end of a link I83 by means of a suitable pivot assembly I 01 similar to that described at 69 above. Pivot assembly I01 is adjustably secured in an arcuate slot I90 formed in segment I84. The other end of link I96 is pivotally connected to the free end of pressure responsive element 39 by a pivot screw IE8 whose shank extends through a suitable aperture in link 38 into threaded engagement with a lug I99, preferably integral with element 39.

Thus, as element 39 flexes in response to pressure changes in the source, link I95 will be displaced to cause rotation of segment I04 about its pivot at I95. Rotation of segment I94, through the engagement of gear teeth 99 and its, causes rotation of clutch element 9I. Hair spring 98 keeps teeth 96 and I03 in constant engagement and prevents back lash due to wear or other factors. With the parts in the clutch engaged position of Figure 3, spring 84 urges clutch element 'l'I axially into engagement with clutch element 9i with the friction faces at 89 and 94 in driving contact. Any slight longitudinal play which might exist between sleeve I6 and clutch element 9! when the parts are in clutch release position is now taken up under the action of spring 8 and the inner end of clutch element 9| abuts firmly against ring IOI.

Sleeve '53 is therefore connected to clutch element 9! by a frictional drive connection so that the above described rotation of clutch element 9! due to actuation of element 39 causes rotation of sleeve 75 and the recorder arm bracket 8i mounted thereupon about shaft 5| as an axis. Pressure element 39 and the segment and gear drive for sleeve 76 are preferably so designed that bracket 8! swings about its axis approximately six times as fast as bracket BI, but it will be understood that any desired ratio between the amplitudes of movement of the recorder arms may be chosen.

A suitable manually operable clutch control member will now be described. Casing 22 is provided with a threaded wall aperture in which is sectued an externally threaded hollow socket HI having a headed portion II2 adapted to seat in a suitable depression II3 upon the outer surface of the casing wall. Socket III is provided with an internal annular seat I I4 in its head portion I52 and a second internal annular seat H5 of smaller diameter axially displaced inwardly from seat II4.

A plunger l 59, having an enlarged knurled head I i? exteriorly of casing 22, is slidably mounted within socket HI. Adjacent head III, plunger i :E is provided with an enlarged shouldered portion H8 which is slidably disposed within head H2. Plunger II 6 extends into the interior of the casing past the inner end of socket III and is there formed with an enlarged, smooth surfaced button or head I19 formed preferably of hemispherical shape. A spring I2I, disposed within socket III, surrounds plunger IIS and extends between seat H5 and the lower surface of shoulder IIB to constantly urge plunger IIS toward the exterior of casing 22. Engagement of the button H9 with the bottom of lug III) at the inner edge of socket III limits axial displacement of the plunger in that direction. Seat II4 cooperates with shoulder IIB to limit axial displacement of plunger H6 in the opposite direction.

The inner end of socket III projects beyond the casing wall and is formed with a pair of aligned, open ended, longitudinal guide slots I22, which slidably receive oppositely projecting pins 23 extending diametrically from plunger II6. Socket I I I is cut away along its inner edge for the major portion of its periphery to provide a guide surface I24 for pins I23 as will be later described. In Figure 3 the parts are shown in clutch engaged position with the recorder arm carried by brackct BI in zero or initial position since groove 88 is aligned directly below button II9.

Referring now to Figures 1A and 2, an angularly extending plate I25 i rigidly secured to bracket 8 I b some suitable securing means passing through aperture 82 in leg 82. Plate I25 is provided with an upstanding post I26 coaxial with shaft 5I and a second upstanding post I21, which is also pivotally mounted on plate I25. A pen or recorder arm I28 is provided at its inner end with a boss I29 journaled on post I26. Arm I28 is further provided with an arcuate slot I3I concentric with shaft 5|. Post I2! extends upwardly through slot I3I- and is provided with a diametrically extending threaded bore for receiving the threaded shank of an adjustment screw 32 whose enlarged knurled head abuts against edge of a hollow supporting boss I33 on arm In this manner pen arm I28 can be adjusted about the axis of shaft 5i with respect to bracket 8| merely by rotating screw I32. At its outer end pen arm I28 is provided with a marking head I34 carrying a marking point or pen of any suitable type or design (not shown). A second pen arm I35 is adjustably mounted upon bracket 6| in substantially the same manner that pen arm I28 is supported upon bracket 8I. Since the specific adjustable mounting of the pen arms with respcct to their brackets BI and SI is not a necessary part of the present invention, it is believed that no more detailed description of the same is necessary. Plate 48 is cut away at I36 to permit full swinging motion of brackets BI and SI.

Operation The operation of the above described recorder as used in earth boring operations will now be described. Conduit i8 is connected to a suitable fiuid pressure source actuated by the bit supporting cable so that the recorder will be responsive to the bit loads upon the cable. During the operations preliminary to drilling, pen arm I28 is maintained inoperatively at zero position at a suitable portion of the chart by the depressed plunger H5, which forces apart the friction clutch surfaces at 89 and 94 as described above. The boring tool or bit to be employed is mounted in the hole to be bored and is suspended in the hole until its total suspended weight is carried by the cable and the bottom of the bit almost touches the bottom of the hole. With the bit in this position, the cable will actuate the pressure source to cause pressure to be transmitted simultaneously to pressure responsive elements 38 and 39.

As explained above, distortion of element 38 due to pressure causes proportionate rotation of bracket 9!; and recorder arm I35, carried by bracket 3!, will rotate in a counter-clockwise direction (Figure l) to trace a record of the total suspended load. Hence, with the bit almost at the bottom of the hole, record pen I35 will indicate the total weight of the drill, which is the maximum suspended load that can be obtained.

Ihe bit is then slowly lowered into contact with the bottom of the hole and is set to produce a predetermined load at the bottom of the hole corresponding to the desired drilling pressure. The moment the bit touches the bottom of the hole the suspended load begins to decrease. This fact is recorded by arm dication is on such a small scale that small variations cannot be precisely noted.

At this point, clutch members as and 94 are engaged by withdrawing plunger Iifi, until head H9 is clear of clutch member ii, and the parts are urged into clutch engaged position by the action. of coil spring ed as explained above. Pen arm IE3 will not move at this time because the suspended load has not been varied. Arm I28 and supporting bracket M are now connected to be actuated concomitantly by pressure responsive element 3%, as described above. Arm ass travels in a clockwise direction over chart 33 concomitantly with arm I35 and with an amplitude of movement six times that of arm I35.

The record traced by arm I23 will therefore be u an amplified record of the fluctuations in the load on the bottom of the hole during drilling operations. By watching carefully the record made by arm M3, the operator is informed of slight fluctuations in load which would not be readily apparent or noticeable in the lower amplitude record and is guided thereby and enabled to precisely set and maintain a predetermined load on the bottom of the hole during drilling perations according to data which has been computed beforehand by the engineering Offi and the record on the chart is a measure of his efr" ciency.

As soon as drilling operations are over, plunger H3 is depressed to separate clutch elements Ti and at before the bit load is removed so that arm itii will not be subjected to injurious load conditions. Depression of plunger H6 causes head I if) to engage the conical surface 88 of clutch element ill, which has been rotated in a clockwise direction (Figure l) by clutch element 9!. Continned depression of plunger II 6, by reason of engagement between the surface of head Ill] and surface will displace element ll axially of sleeve l3 and shaft until the clutch surfaces at and as are separated.

By this time pins I23 will have been displaced below surface I24 and plunger I I6 can now be rotated to bring pen arm I23 back to initial or zero position at the outer edge of the chart. It will be observed that the lateral edge of lug Ill) permits rotation of plunger IE6 only in a clockwise direction (looking down in Figure 3). After pins E23 have been rotated beyond alignment with slots IZil, inward pressure on plunger H6 can be release l and pins I23 will slide along guide surface I224 the plunger is rotated. Since surface 86 the bottom surface of button H9 are in tight frictional engagement, rotation of plunger H5 will cause rotation of clutch element 1'! and the but that recorded ini pen arm bracket 8I in a counter-clockwise direction as seen in Figure 1. Upon continued rotation of plunger I IS, in the same direction surface 86 will beturned until button I I9 falls into groove 88. This indicates that the recorder arm is at zero or initial position, and plunger H8 can now be rotated in either direction without further rotation of clutch element 2?? since the contacting surfaces of button HQ and groove 88 are smooth and the pressure now exerted by spring 84 is not sufficient to establish a frictional drive between button H9 and the surface of groove 83. Furthermore, spring 34 is coiled about the shank of element l? in such a manner that it resists rotation of element ill with respect to sleeve I6 in a direction opposite that involved in returning arm iii! to initial position.

After button IIii falls into groove 88, the operator releases knob ill, and plunger H6 is held in clutch disengaging position by the engagement of pins I23 and surface I24. Further manipulation of knob I I7 is unnecessary until it is desired to reengage the clutch elements for recording the load on the bottom during subsequent drilling operations. It is then necessary only to rotate knob II'I until pins I23 become aligned with slots I22 and abut against the lateral edge of lug H0. Release of knob Iii will then permit spring I2I to force plunger 1E6 outwardly to separate button H9 from clutch element 11 and permit driving engagement between clutch elements I! and d4.

Although the invention has been described above as appliedto a recorder the same principle can also be 'used in any other indicating instruments. In the recorder embodiment above described, any relative movement between the chart and the recorder arms may be arranged; and, if desired,the recorder arms may be caused to make their records on separate charts moved in synchronism without departing from the broad principle of the invention.

It will further be understood that application of the invention is by no means limited to the measurement. of boring tool pressures as above described but may be applied broadly to the measurement and study of any conditions.

The invention may be embodied in other spe cific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. Exhibiting apparatus adapted to support a scaled member, a pair of separate exhibitor arms for making separate indications on said scaled member, means for actuating each arm in response to forces derived from a common source, one of said arms being designed for amplified movement along said scaled member with respect to the other of said arms, separable clutch ele ments in the actuating means for said one arm, means for separating said clutch elements to prevent said one arm from being actuated by its actuating means and means for reengaging said clutch elements at any desired point in the operation of said other arm for obtaining a magnified indication of said forces over a predetermined period.

2. Exhibiting apparatus as defined in claim 5, wherein the ratio of movement of the separate arms while they operate in synchronism is of the order of 6 to 1 and the arms move in opposite directions across said scaled member.

3. Recording apparatus comprising a support, a movable chart upon said support, a pair of recording members adapted to make separate records upon said chart, separate pressure responsive elements connected to each of said members, and means for connecting both of said elements to the same source of pressure, one of said pressure responsive elements being of such design and so connected to its recording member as to cause that member to make an amplified record with respect to the other of said members, and selectively operable means providing for actuation of one of said members alone or simultaneous actuation of said members by the respective pressure responsive elements.

4. In a recorder, a support, a shaft mounted on said support, a pair of sleeve means rotatable upon said shaft and a separate recording arm secured to each sleeve, means for rotating one of said sleeves and separate means for rotating the other of said sleeves, said last named means including a releasable clutch whereby the recording arm operated thereby may be rendered selectively inoperable or operable in synchronism' with said first named recording arm.

5. In a meter or the like, a support, a shaft mounted upon said support, spaced members rotatable upon said shaft and a separate indicat- 6. In a meter or the like, an indicating arm, means for actuating said arm comprising separable clutch elements, said arm being secured to one of said clutch elements, a device shiftable into engagement with said one clutch element for separating said clutch elements, said device being further shiftable while engaged with said one clutch element to move said arm to a predetermined position with respect to the scale of said meter, and cooperating formations on said one clutch element and said device for rendering said device inoperable to move said arm over said scale after said predetermined position has been reached.

'7. In a meter or the like, an indicating arm, a rotatable clutch element to which said arm is secured, a second clutch element adapted to engage said first named clutch element, a plunger adapted to engage a cooperating formation on said first named clutch element to disengage said clutch elements, said plunger being rotatable to rotate said first named clutch element to move said arm to a predetermined position with respect to the scale of said meter and means interrupting rotation of said first clutch member by said plunger effective when said predetermined position has been reached.

8. In a meter or the like, a rotatable clutch element, an indicating arm secured to said element, an inclined surface on said element, a plunger on said meter adapted to be advanced into engagement with said inclined surface and being rotatable so that rotation of said plunger effects rotation of said clutch element by reason of the frictional engagement therebetween and means at said surface for preventing further r0- tation of said plunger from moving said arm after the latter has reached a predetermined position With respect to the scale of the meter.

l/IAXIMILIAN KLEIN. REIDAR A. TOLLEFSEN.

CERTIFICATE OF CORRECTION. I Patent-No. 2,2b,8,l+29. July 8, 19th.

MAXIMILIAN KLEIN, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page-6, first column, line 5, claim 2, for the claim'ref'erence numeral "5'f read --l--; and that thesaid Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office. I

Signed and sealed this 12th day of August, A. D. 1914.1,

Henry Van Airedale,- (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION. I Patent No. 2, 2l+8,l|.29. July 8, 19 41.

MAXIMILIAN KLEIN, ET AL.

It is hereby certified that error appears in the printed specification 'of the above numbered patent requiring correction ass follows: Page-6, first column, line 5, claim 2, for the claim'reference nwrgeral "5'l read --l.--; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in' the Patent Office. i

Signed and sealed this 12th day of Au ust, A. 1). 19m,

M Henry Van Arsdale; (Seal) Acting Commis sioner of Patents. 

